RFA: Allow RTX_FRAME_RELATED_P to accept SEQUENCEs

[Nick Clifton]

Hi Guys,

  The arm-elf port is currently failing to be because it attempts to
  set RTX_FRAME_RELATED_P on a SEQUENCE and this is not allowed.  The
  insn is being generated in arm.c:emit_multi_reg_push() and there is
  a comment there to explain why:

  /* For the body of the insn we are going to generate an UNSPEC in
     parallel with several USEs.  This allows the insn to be recognised
     by the push_multi pattern in the arm.md file.  The insn looks
     something like this:

       (parallel [ 
           (set (mem:BLK (pre_dec:BLK (reg:SI sp)))
	        (unspec:BLK [(reg:SI r4)] UNSPEC_PUSH_MULT))
           (use (reg:SI 11 fp))
           (use (reg:SI 12 ip))
           (use (reg:SI 14 lr))
           (use (reg:SI 15 pc))
        ])

     For the frame note however, we try to be more explicit and actually
     show each register being stored into the stack frame, plus a (single)
     decrement of the stack pointer.  We do it this way in order to be
     friendly to the stack unwinding code, which only wants to see a single
     stack decrement per instruction.  The RTL we generate for the note looks
     something like this:

      (sequence [ 
           (set (reg:SI sp) (plus:SI (reg:SI sp) (const_int -20)))
           (set (mem:SI (reg:SI sp)) (reg:SI r4))
           (set (mem:SI (plus:SI (reg:SI sp) (const_int 4))) (reg:SI fp))
           (set (mem:SI (plus:SI (reg:SI sp) (const_int 8))) (reg:SI ip))
           (set (mem:SI (plus:SI (reg:SI sp) (const_int 12))) (reg:SI lr))
        ])

      This sequence is used both by the code to support stack unwinding for
      exceptions handlers and the code to generate dwarf2 frame debugging.  */

  So - I would like permission to apply the following patch which
  amends the definition of RTX_FRAME_RELATED_P to accept SEQUENCEs.

Cheers
        Nick

2002-05-16  Nick Clifton  <nickc@cambridge.redhat.com>

	* rtl.h (RTX_FRAME_RELATED_P): Accept SEQUENCEs.

Index: gcc/rtl.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/rtl.h,v
retrieving revision 1.347
diff -c -3 -p -w -r1.347 rtl.h
*** gcc/rtl.h	13 May 2002 04:50:11 -0000	1.347
--- gcc/rtl.h	16 May 2002 14:54:59 -0000
*************** do {				\
*** 520,527 ****
  #define RTX_UNCHANGING_P(RTX)						\
    (RTL_FLAG_CHECK3("RTX_UNCHANGING_P", (RTX), REG, MEM, CONCAT)->unchanging)
  #define RTX_FRAME_RELATED_P(RTX)					\
!   (RTL_FLAG_CHECK5("RTX_FRAME_RELATED_P", (RTX), INSN, CALL_INSN,	\
! 		   JUMP_INSN, BARRIER, SET)->frame_related)
  
  /* 1 if RTX is an insn that has been deleted.  */
  #define INSN_DELETED_P(RTX)						\
--- 520,527 ----
  #define RTX_UNCHANGING_P(RTX)						\
    (RTL_FLAG_CHECK3("RTX_UNCHANGING_P", (RTX), REG, MEM, CONCAT)->unchanging)
  #define RTX_FRAME_RELATED_P(RTX)					\
!   (RTL_FLAG_CHECK6("RTX_FRAME_RELATED_P", (RTX), INSN, CALL_INSN,	\
! 		   JUMP_INSN, BARRIER, SET, SEQUENCE)->frame_related)
  
  /* 1 if RTX is an insn that has been deleted.  */
  #define INSN_DELETED_P(RTX)						\